Definition
A measuring and layout tool with two legs of different shapes: one straight leg that ends in a sharp scribing point, and one curved leg that hooks over an edge. The tool is used to scribe a line parallel to the edge of a piece of material, or to locate the center of a round bar.
Plain English
A two-legged tool where one leg hooks onto the edge of a part and the other leg has a sharp tip that scratches a mark a set distance from that edge.
Context Anchor
Seen in aircraft maintenance and repair work, especially when laying out marks on metal before cutting, drilling, or shaping a part.
Derivation
The name comes from the tool having two different kinds of legs on one body — one shaped like a divider leg (straight, pointed) and one shaped like a caliper leg (curved). Because it combines features of two different tools in one, it was called 'hermaphrodite,' from the Greek meaning 'having two natures.'
Why Pilots Care
Pilots performing owner-allowed maintenance or working alongside an A&P during sheet metal repairs may see this tool used to mark accurate, repeatable lines along the edge of a skin or part before cutting or drilling.
Analogy
Think of it like a compass where one side follows the edge of the material instead of staying fixed in one spot, while the other side draws the line.
Intuition Check
Do not read this as a biology term in this context. Here, hermaphrodite simply means the tool has two different types of legs combined in one tool.
Example Sentence 1
The mechanic used hermaphrodite calipers to scribe a line one-half inch from the edge of the aluminum skin before drilling the rivet holes.
Example Sentence 2
Hermaphrodite calipers helped locate the center of the round steel bar before drilling the mounting hole.